Unit 0: Research Methods

Module 1: The Need for Psychological Science

Key Concepts:

  • Hindsight Bias: Tendency to believe we "knew it all along" after an outcome has occurred. Example: Predicting a sports outcome post-game.

  • Overconfidence: We often overestimate our accuracy or knowledge. Example: Decca Records famously rejected The Beatles.

  • Perceiving Patterns in Random Events: Seeing order in random occurrences (e.g., Gambler's Fallacy).

Main Point: Science helps us separate intuition from reality using systematic inquiry.

Module 2: The Scientific Method

Steps:

  1. Identify a problem.

  2. Formulate a hypothesis.

  3. Design a method.

  4. Collect data.

  5. Analyze results.

  6. Conclude.

  7. Report findings.

Key Terms:

  • Theory: An explanation that organizes observations and predicts outcomes.

  • Hypothesis: A testable prediction.

  • Operational Definitions: Precise definitions to ensure replicability.

  • Replication: Repeating studies to confirm findings.

  • Critical thinking: the ability to analyze, evaluate, and synthesize information in a reasoned, logical, and unbiased manner.

  • Placebo effect: The improvement of symptoms with no actual treatment.

  • Scatterplot: a graph that visually represents the relationship between two variables.

    • Positive skew: a type of distribution where the values are more spread out on the right side (tail) of the distribution graph. (mean will be greater than the median)

    • Negative skew: Data that is negatively skewed have a long tail that extends to the left.(median will typically be greater than the mean.)



Research Types/Methods:

  • Descriptive: Observes and records behavior (e.g., case studies, surveys).

  • Experimental: Manipulates variables to identify cause-and-effect relationships.

  • Correlational: Identifies relationships but not causation.

  • Case study: A detailed investigation of a single individual, group, or event, often used to explore rare phenomena or gain deep insights into complex issues. 

  • Meta-analysis: the statistical combination of results from two or more separate studies.

  • Naturalistic observation: involves observing behavior in its natural environment without intervention. This method helps researchers understand behaviors as they naturally occur, but it may lack control over variables.

  • Surveys: A research method involving questionnaires or interviews to gather data about individuals’ thoughts, attitudes, or behaviors. Surveys are useful for quickly collecting large amounts of data, but they depend on self-reported information, which can sometimes be biased.

  • Longitudinal Research: A study conducted over an extended period, tracking the same individuals to observe changes over time. This approach is valuable for identifying developmental or long-term trends.

  • Cross-Sectional Research: A study comparing different groups at a single point in time to analyze differences and trends. Unlike longitudinal studies, cross-sectional research provides a snapshot rather than a long-term view.

  • Structured interviews: a standardized method of assessment in which the interviewer asks a predetermined set of questions as-written and records patient responses.

  • Likert scale: a rating scale used to measure survey participants' opinions, attitudes, motivations, and more.

  • Replication: The process of repeating a study to confirm its findings and ensure reliability.

  • Falsifiability: A criterion for a scientific theory, requiring it to be testable and able to be proven wrong.

  • Social desirability bias: Tendency of participants to respond in ways that are socially acceptable rather than truthful.

Module 3: Correlation vs. Experimentation

Correlation: a statistical technique that is used to measure and describe a relationship between two variables.

  • Correlation Coefficient: indicates a measure of the direction and strength of a relationship between two variables.

  • Positive Correlation: Both variables increase/decrease together. 

  • Negative Correlation: One variable increases as the other decreases.

  • Illusory Correlation: Perceived relationships that don't exist.

  • Directionality problem: Difficulty in determining whether variable A causes variable B or vice versa.

  • 3rd-variable Problem: Occurs when an unmeasured third variable influences the relationship between two other variables.

Experimentation:

  • Independent Variable: Factor manipulated.

  • Dependent Variable: Outcome measured.

  • Confounding Variables: something that potentially affects the results of a study but is not accounted for

  • Control Group: Does not receive treatment.

  • Experimental group: Receives the treatment

  • Random Assignment: Equal distribution to avoid bias.

  • Placebo Effect: Improvement due to expectations alone.

  • Single-Blind procedure: Only the participants are unaware of which group (e.g., treatment or control) they belong to. However, the researchers are fully aware of the group assignments.

  • Double-Blind procedure: Neither the participants nor the researchers involved in administering the experiment know the group assignments. 

  • Generalizability: the measure of how useful the results of a study are for a larger group of people or situations.

  • Effect size: A measure of the magnitude or strength of a relationship or difference in a study, beyond just statistical significance.

  • Peer review: Evaluation of research by experts in the field before publication, ensuring quality and credibility.

  • Institutional review: Oversight by an institutional review board (IRB) to ensure ethical standards in research involving human participants.

  • Sample: The subset of a population selected for a study.

    • Representative sample: A sample that accurately reflects the characteristics of the larger population.

    • Random sampling: Selecting participants randomly to ensure unbiased representation.

    • Convenience sampling: a method where the selection of participants is based on their ready availability.

Module 4: Statistical Reasoning

Measures of Central Tendency:

  • Mean: Average score.

  • Median: Middle score when ordered.

  • Mode: Most frequent score.

Measures of Variability:

  • Range: Difference between the highest and lowest scores.

  • Standard Deviation: Indicates consistency of scores around the mean.

  • Bimodal distribution: a type of distribution characterized by two distinct peaks.

  • Normal Curve: Bell-shaped distribution representing data spread.

  • Quantitative data: tells us how many, how much, or how often in calculations. 

  • Qualitative data: can help us to understand why, how, or what happened behind certain behaviors.

  • Statistical significance: Indicates whether the results of a study are likely due to chance or reflect a true effect.

Module 5: Ethical Guidelines

For Humans:

  • Obtain informed consent (giving a patient the special knowledge that makes him/her competent to take decisions in a more informed way.). And informed assent (Agreement from participants who may not fully understand the research (e.g., children), often requiring parental consent.)

  • Protect participants' confidentiality (Protecting participants' privacy by not disclosing personal information.)

  • Debrief (Informing participants about the full purpose and details of a study after its conclusion.) participants post-study.

  • Avoid harm and deception unless necessary.

  • Secure Institutional Review Board (IRB) approval.